Finite Size Scaling Analysis of Proton Cumulants

We perform a finite-size scaling analysis of net-proton number cumulants in Au+Au collisions at center-of-mass energies between 2.4 GeV and 54.4 GeV to search for evidence of a critical point in the QCD phase diagram. We take measurements in different rapidity bin widths, corresponding to different subvolumes of the system, as probes of different length scales. We use model simulations to verify the applicability of this approach, then apply it to data and find evidence for a critical point near the baryon chemical potential of μB ≈ 625 MeV and temperature of T ≈ 140 MeV. This is the first analysis of experimental data to locate the critical point in a range consistent with theoretical predictions.